1. Field of the Invention
The present invention relates to an electric-powered compressor having a compression mechanism for sucking in and compressing a refrigerant, an electric motor for driving the compression mechanism, and an inverter circuit or other motor drive circuit for driving the motor and is effective if applied to a vehicular steam compression type refrigeration cycle.
2. Description of the Related Art
As an electric-powered compressor of the related art, for example, as described in Japanese Unexamined Patent Publication No. 2000-291557, there is known one comprised of a compression mechanism and a motor formed integrally and having a drive circuit for driving the motor attached to the refrigerant gas suction side of the compression mechanism. More specifically, the housing in which the motor is housed is provided with a refrigerant suction port and the inverter in the drive circuit is attached in close contact with the housing of the motor.
Due to this, the semiconductor switching device in the inverter is cooled by the low temperature refrigerant during the motor operation, so no air-cooled radiator or fan or water-cooled radiator or water piping etc. are necessary and the electric-powered compressor can be made small in size and low in cost.
In the above art, however, the idea of positively cooling the control circuit for controlling the operation of the semiconductor switching device in the drive circuit has never been seen. In general, the heat generated by the control circuit itself is less than the semiconductor switching device, but its own heat resistance is low, so there was the problem that when the motor was not being operated, the reliability could not be sufficiently secured depending on the temperature environment in which the electric-powered compressor was arranged.